From f9c548219b6543959dd240618f8a922fdbcabc6d Mon Sep 17 00:00:00 2001 From: Matthew Heon Date: Fri, 15 Feb 2019 10:33:59 -0500 Subject: Recreate SHM locks when renumbering on count mismatch When we're renumbering locks, we're destroying all existing allocations anyways, so destroying the old lock struct is not a particularly big deal. Existing long-lived libpod instances will continue to use the old locks, but that will be solved in a followon. Also, solve an issue with returning error values in the C code. There were a few places where we return ERRNO where it was not set, so make them return actual error codes). Signed-off-by: Matthew Heon --- libpod/lock/shm/shm_lock.c | 6 ++++-- libpod/runtime.go | 26 ++++++++++++++++++++------ 2 files changed, 24 insertions(+), 8 deletions(-) diff --git a/libpod/lock/shm/shm_lock.c b/libpod/lock/shm/shm_lock.c index 367055823..d11fce71a 100644 --- a/libpod/lock/shm/shm_lock.c +++ b/libpod/lock/shm/shm_lock.c @@ -203,6 +203,8 @@ shm_struct_t *setup_lock_shm(char *path, uint32_t num_locks, int *error_code) { // terminating NULL byte. // Returns a valid pointer on success or NULL on error. // If an error occurs, negative ERRNO values will be written to error_code. +// ERANGE is returned for a mismatch between num_locks and the number of locks +// available in the the SHM lock struct. shm_struct_t *open_lock_shm(char *path, uint32_t num_locks, int *error_code) { int shm_fd; shm_struct_t *shm; @@ -255,11 +257,11 @@ shm_struct_t *open_lock_shm(char *path, uint32_t num_locks, int *error_code) { // Need to check the SHM to see if it's actually our locks if (shm->magic != MAGIC) { - *error_code = -1 * errno; + *error_code = -1 * EBADF; goto CLEANUP; } if (shm->num_locks != (num_bitmaps * BITMAP_SIZE)) { - *error_code = -1 * errno; + *error_code = -1 * ERANGE; goto CLEANUP; } diff --git a/libpod/runtime.go b/libpod/runtime.go index bc7c061c4..850df4fc9 100644 --- a/libpod/runtime.go +++ b/libpod/runtime.go @@ -7,6 +7,7 @@ import ( "os/exec" "path/filepath" "sync" + "syscall" "github.com/BurntSushi/toml" is "github.com/containers/image/storage" @@ -757,12 +758,6 @@ func makeRuntime(runtime *Runtime) (err error) { aliveLock.Unlock() } }() - // If we're renumbering locks, do it now. - // It breaks out of normal runtime init, and will not return a valid - // runtime. - if runtime.doRenumber { - return runtime.renumberLocks() - } _, err = os.Stat(runtimeAliveFile) if err != nil { @@ -785,6 +780,18 @@ func makeRuntime(runtime *Runtime) (err error) { manager, err := lock.OpenSHMLockManager(lockPath, runtime.config.NumLocks) if err != nil { if os.IsNotExist(errors.Cause(err)) { + manager, err = lock.NewSHMLockManager(lockPath, runtime.config.NumLocks) + if err != nil { + return err + } + } else if err == syscall.ERANGE && runtime.doRenumber { + // ERANGE indicates a lock numbering mismatch. + // Since we're renumbering, this is not fatal. + // Remove the earlier set of locks and recreate. + if err := os.Remove(filepath.Join("/dev/shm", lockPath)); err != nil { + return errors.Wrapf(err, "error removing libpod locks file %s", lockPath) + } + manager, err = lock.NewSHMLockManager(lockPath, runtime.config.NumLocks) if err != nil { return err @@ -795,6 +802,13 @@ func makeRuntime(runtime *Runtime) (err error) { } runtime.lockManager = manager + // If we're renumbering locks, do it now. + // It breaks out of normal runtime init, and will not return a valid + // runtime. + if runtime.doRenumber { + return runtime.renumberLocks() + } + // If we need to refresh the state, do it now - things are guaranteed to // be set up by now. if doRefresh { -- cgit v1.2.3-54-g00ecf